The campaign was given a lift by celebrity Twitter endorsements from George Takei and Sean Lennon.

Brusaw, who launched Solar Roadways with his wife, Julie, says the funds will be used to open an office, hire staffers and test his prototype in Sandpoint, Idaho, which wants to be the first city to have them.

The concept has also received interest from an Amtrak station and the Sandpoint Airport, but they'll start with footpaths and car parks in town in the spring, Brusaw says.

"At the end of this year, we'll have a finished product," Brusaw said.

"It's not going to happen overnight — there's a learning curve here. Once we're convinced the final product works in a parking lot, we'll try residential roads. Then, eventually, the fast lane of a highway."

An artist's rendition of a motorway lined with solar panels. Source: Solar Roadways

According to his calculations, the "smart" solar panels — encased in double-layered, bomb-resistant, bulletproof glass capable of withstanding 250,000 pounds — would, among other things, be able to generate "three times the electricity currently used in the United States," prevent accidents by melting snow and ice (and warning drivers of debris in the road with solar-powered LED lights) and even collect storm water. Oh, and cut greenhouse emissions by as much as 75 percent.

Brusaw, a former Marine Corps weapons technician, says he and his wife came up with the idea after watching Al Gore's film "Inconvenient Truth."